It is well known that open chimney flues present opening for unwanted admission of rain, insects, animals, and birds to homes or other buildings. Further it is well known that significant heat loss occurs through open chimney flues during the winter when a damper or other means is not provided to close off the chimney opening when there is not fire in the associated fireplace.
Various means have been provided for closing a chimney or flue when not in use such as the well known fire box damper, and various other prior arrangements. Some such prior arrangements are illustrated in U.S. Pat. No. 2,704,502, Rainey; and U.S. Pat. No. 2,856,839, Soderberg, as well as U.S. Pat. No. 3,267,832, Hinkle.
Such prior arrangements have certain disadvantages and it is an object of the present invention to overcome many of the difficulties encountered in the use of the prior art arrangements.
Specifically, such previous arrangements have permitted wind blown rain to enter the chimney even though the damper located at the top of the chimney is closed. Moreover in most such arrangements it has been provided for the damper to be normally closed so that when the means to secure the damper are not functioning the damper is in a closed position and if a fire is built in the fireplace, when the damper is closed, the associated rooms are filled with smoke.
In an arrangement shown in U.S. Pat. No. 3,945,307, Lyemance, a normally open damper arrangement is shown to include a sealing arrangement to prevent leakage of rain or snow into the chimney which further provides a seal to reduce heat loss from the chimney. It has been found that such normally open dampers, which provide safety features that the damper normally fails to open freezing rain and snow, under severe conditions prevent opening of the damper.